MILITARY STANDARD MOBILITY, TOWED AND MANUALLY SUPPORT EQUIPMENT

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1 NOTICE 1 18 December 1990 MILITARY STANDARD MOBILITY, TOWED AND MANUALLY SUPPORT EQUIPMENT PROPELLED TO ALL HOLDERS OF MIL-STD-1784A 1. PAGES 9 AND 28 OF MIL-STD-1784A HAVE BEEN REVISED AND SUPERSEDE PAGES 9 AND 28 OF THAT DOCUMENT DATED 29 JUNE PAGES 10 AND 27 ARE REPRINTED WITH NO CHANGES. 2. REPLACE PAGES 9-10 AND OF MIL-STD-1784A WITH THE NEW PAGES 9-10 AND ATTACHED. FILE THIS NOTICE WITH MIL-STD-1784A. 3. Holders of MIL-STD-1784A will verify that the page changes indicated above have been entered. This notice will be retained as a check sheet. This issuance, together with appended pages, is a separate publication. Each notice is to be retained by stocking points until the military standard is completely revised or canceled. INFORMATION SUBJECT TO EXPORT CONTROL LAWS This document contains information subject to the International Traffic in Arms Regulation (ITAR) and/or the Export Administration Regulation (EAR) of 1979 which may not be exported, released, or disclosed to foreign nationals inside or outside the United States without first obtaining an export license. A violation of the ITAR or EAR may be subject to a penalty of up to 10 years imprisonment and a fine of $100,000 under 22 U.S.C 2778 or Section 2410 of the Export Administration Act of Include this notice with any reproduced portion of this document. DESTRUCTION NOTICE For classified documents, follow the procedures in DoD M Industrial Security Manual, Section or DoD R, Information Security Program Regulation, Chapter IX. For unclassified, limited documents, destroy by any method that will prevent disclosure of contents or reconstruction of the document. Custodian: Preparing activity: Air Force - 11 Air Force - 11 Project No F168 AMSC N/A FSC 1740

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3 TABLE III. Coefficients for random road roughness Track width. The track width of all axles on the equipment shall be between and inches Manual propulsion. The equipment shall be maneuverable by person/people. The maximum force required to move the equipment shall not exceed those specified in MIL-STD Means shall be provided for adequate handling of the equipment. Handholds and grasps, if used, shall also conform Towing. The equipment shall be designed for towing by. Trailers shall be designed to permit towing, in train, up to fully loaded trailers of the same weight and size behind a prime mover Trailers shall be towable at constant speed on a level concrete or macadam surface with a drawbar load not exceeding pounds per ton of GVW. The trailer, when towed in a straight line, on a level surface at constant speed, shall track within inches of the prime mover. Power assist or self propulsion features, if employed on the trailer, shall not affect the force required for normal towing Towbar. The towbar shall be equipped with a lunette (towbar eye) conforming to MS Except for three-quarter trailers, the towbar shall be detachable from the equipment. Towbars on three wheel and full trailers shall be hinged and provided with a convenient and positive hold in the up (Vertical) position that works at all turning angles of the wheels. To keep a horizontal line of action for the force between the trailer and the prime mover, the height of the towbar, when parallel to the ground (measured from the ground to the horizontal centerline of the lunette), shall be within plus or minus inches of the height of the pintle assembly on the prime mover. If a prime mover has not been specified the height of the towbar shall be no more than inches. The force at the lunette required to lift a hinged towbar to its towing position shall not exceed 50 pounds (222 Newtons) Pintle assembly. If tandem towing is required, trailers shall be equipped with a rear mouonted pintle assembly that will transfer towing forces directly and evenly to the chassis frame members. Pintle assemblies shall conform to the following standards as applicable: Capacity (pounds) up to 18,000 18,001 to 40,000 40,001 to 100,000 Standard MS MS MS Supersedes page 9 dated 29 June

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5 APPENDIX TABLE II. Mobility courses obstacles. 27

6 APPENDIX TABLE III. Coefficients for random road roughness. been in use for many years. Information on the use of PSD equations to describe road roughness can be found in Dynamic Terrain Inputs to Predict Structural Integrity of Ground Vehicles, a report by Mike Sayers at the University of Michigan Transportation Research Institute. The constants in the PSD equation were selected to represent typical surfaces around the world. Wavelengths longer than 100 feet have little effect on vehicles traveling no faster than 30 mph; the same IS true of wavelengths longer than 50 feet for vehicles traveling no faster that 15 mph. Due to the natural filtering characteristics of tires, the equation is not accurate for wavelengths less than the tire footprint length. REQUIREMENT GUIDANCE The recommended mileage requirement per year of expected life is as follows: Type/Class Mileage (per year of expected life) Type I, class 1a 25 (40 km) Type I, class 1b 75 (121 km) 250 (402 km) Type I, class 3 25 (40 km) Type II 750 (1207 km) 28